footer {
    position: fixed;
    left: 0;
    bottom: 0;
    width: 100%;
    height: 50px;
    line-height: 50px;
    text-align: center;
    background-color: white;
}
footer ul {
    list-style: none;
    display: flex;
    padding-inline-start: 0;
}
footer ul li {
    flex: 1;
}
footer ul li .active{
    color: red;
}
